Positioning control for hydraulic motors



Oct. 20, 1953 R. TYLER POSITIONING CONTROL FOR HYDRAULIC MOTORS FiledSep'c. 18, 1950 2 Sheets-Sheet l ATTORNEY Oct. 20, 1953 R. TYLERROSITIONING CONTROL ROR HYDRAULIC MOTORS Filed Sept. 18, 1950 2Sheets-Sheet 2 l 5 \|1 .M 5 b2 3 Ml 9 .a L elm I7 o 0:/ O5/ c 5 0 gv O OO .u a 2 b P I G b l S \|b l C R .u S L 4 R F .l l- 5 s C L .2 w G:\ cqo 4 l S 4 w o O A. mi o c 2 3 7 3 3 7 9 5 o 7 5 c 2 l 5 2 R S o 9 7 s Wcl R 4 nm. 3 b2 .nM/ d d 3 R R 5, m 2: C 2:2 w OF L a m. 2 5 C C m2 /4 WR m 3 m.l m2 4 y :n l \G C 5 W 7W W INVENTOR RANSOM TYLER ATTORNEYPatented Oct. 20, 1953 UNITED STATE TENT OFFICE POSITIONING CONTROL FORHYDRAULIC MOTORS tion of Wisconsin Application September 18, 1950,Serial No. 185,487

11 Claims. 1

This invention relates to apparatus for controlling the operation ofhydraulic motors and it has as an object to provide a control which willcause a hydraulic motor to move a machine element or the like to aposition which is determined by the adjustment of the control.

Another object is to provide a control which will cause a hydraulicmotor to move an element into and positively hold it in a predeterminedposition.

The control is particularly adapted for effecting movement of the saw ofa sawmill into selected positions but it may be used for many otherpurposes.

The invention is exemplified by the control shown schematically in theaccompanying drawings in which the views are as follows:

Fig. 1 is a diagram of the hydraulic circuit of a motor to which theinvention has been applied.

Fig. 2 is a plan view taken on the line 2-2 of Fig. 1 but drawn to alarger scale.

Figs. 3 and 4 are views showing the plunger or valve element of acontrol Valve in positions different from those shown in Fig. l.

Fig. 5 is a diagram of the electric circuit.

Fig. 6 is a diagram of the switches shown in Fig. 5.

The hydraulic motor may be of the reciprocating type and have its pistonrod connected to the element to be moved or it may be of the rotary typeand be connected to the element through a suitable drive such as a rackand pinion or a chain and sprocket drive. As shown, the hydraulic motorincludes a stationary cylinder I and a piston 2 which is iitted incylinder I and is connected by a piston rod 3 to a lug II fixed to acarriage 5 only a fragment of which has been shown as it forms no partof the invention.

Liquid for energizing motor I-2 is supplied by a continuously drivenpump 6 which draws liquid from a reservoir 'I and discharges it througha channel 8 into a control valve which may be of any suitable type. Asshown, the control valve has a valve member or plunger 9 iitted in avalve body I9 which is connected by two channels II and I2 to oppositeends of cylinder I. Communication between channel 8 and channels II andI2 is controlled by plunger 9 which also controls communication betweenthose channels and an exhaust channel I3 which is connected to body I0and discharges into reservoir l.

o Plunger 9 is urged to and normally held in its central or neutralposition by two springs I4 and I5, which are arranged in the oppositeend portions of body I0, and it is adapted to be shifted in onedirection or the other by one or the other of two solenoids SI and S2which are connected to plunger 9 by a suitable linkage I9.

The arrangement is such that, when neither of solenoids SI or S2 isenergized, valve plunger 9 is held in its neutral position by springs I4and I5 in which position of plunger 9 channel 8 is connected through theinterior of plunger 9 and body Ill to channel I3 so that pump 6 isbypassed and the ends of channels II and I2 are blocked by plunger 9 sothat piston 2 cannot move.

When solenoid SI is energized, it will shift plunger 9 toward the rightinto the position shown in Fig. 3 and then the liquid discharged by pumpt will fiow through channel 8, valve body III and channel II into theleft end of cylinder I and cause piston 2 to move carriage 5 toward theright. The liquid ejected by piston 2 from the right end portion ofcylinder I will Iiow through channel I2, Valve body I9 and channel I3into reservoir l.

When solenoid S2 is energized, it will shift plunger 9 toward the leftinto the position shown in Fig. 4 and then the liquid discharged by pump6 will flow through channel 8, valve body I9 and channel I2 into theright end of cylinder I and cause piston 2 to move carriage 5 toward theleft. The liquid ejected by piston 2 from the left end portion ofcylinder I will flow through channel II, valve body I0 and channel I 3into reservoir 1.

Solenoids SI and S2 are adapted to be energized selectively by theelectric circuit shown in Fig. 5, a solenoid being energized in responseto operation of one or the other of two limit switches LSI and LS2 whichform parts of the electric circuit and which are adjustable intoselected positions in any suitable manner. As shown, switches LSI andLS2 are adapted to be operated by a cam Il', which is movable withcarriage 5 as by being carried by lug d, and they are fastened to aslide I3 which is mounted upon a stationary guide I9. Slide I8 isconnected by a rod 29 to a slide 2! which also is mounted upon guide I9and preferably is frictionally held in adjusted positions by means notshown. Slide 2i is provided with a handle 22 for moving it and slide I8along guide I9 and with a pointer 23 for indicating the position ofswitches LSI and LSE upon a stationary scale 24.

n Each of limit switches LSI and LS2 includes indica-tee in Fiesafat ficerating position as explained in Patentf2, 2 '97339l 3 a normally opencontact a, a normally closed Contact b and an operating button c, andeach is a microswitch so that depressing button c only a few thousandthsof an inch causes contact a to close and contact b to open.

When handle 2; is moved in either direction to a given "'p'ositi, motorl-I willfnoyefcarriage 5 in' the''sa'me directiorandjas carriage 5approaches a position corresponding to the position to which handle 22was moved, cam Hf? 10 will momentarily depress thelojuttcnat;oriejlirrlit switch and then depress the button of thesec-'5"' ond limit switch which Willcaus'e motor lv t9 stop as willpresently be eXplained-'lie two, limit switches are so locatedi respectto each f other and cam l1 is so shaped that camv l1 will depress thebutton of the scndflimit switch only an instant after it releases the bAtton ofg the erst limit switch.

ander-feg aie @new f That is', when an electric circuit is'j momentarilypassed through a'part'of the'magnt'winding, the A'Iiia'gnet' will raise`the contat'i respect to the drawing; and, duto the risidalfnagnetismin"the` magnet frame, "will hold its 4' contacts; up until thefrar'n'eis/denagnetized bypassing an electricfcirrent'throughthe tirevwinding'whch' will [permit fthe, contacts to' dren." Relay Ril Yis controlled'inpartbyf'a starting switch YSS;garni* in part by" limit switches ns1marisa which also control reiayRzr' MagntCllmf'of contactar Clhas oneendof its winding connected' to fpowerflinefLl and the other end of itsA'winding connected through va Wire 38, Contact -CZCQ v'ag'wire 39contactgRf; ja wir"40;^"contact RIP, and a"wire '4lfto":po er line L2,'f Wire dnisi also' "conrlectregl` through-aja Wire 2,`contact"Cfl' and`a wire'SitdNpowe line L2. "-l l., im; .4..

r`Magnet Cim of contactor C2 has one end of its winding connected topower line L! and th other end of its winding connected through a wireed, contact Cld, a wire i5, contact R22, a wire G6, contact RIa and awire el to power line L2. Wire i6 is also connected through a wire 48,come@ Q?? @11d a viireqtcpower line L2- "MgrietLRl'?? o1 relay "Rl hasone4 en d of its winding connected to power 4line Li 'andthe other endof its winding connected through a wire 5i?, starting switch SS and awire 5I to power line, 1.2;,V `12551133 5g, is*v connected through aWire 52; Contact RIC, a wire 53, contact LSlb, a wire 551,cQltilLgPnapda Wire 55 to power line L2. `R mpfre'lay R2 has one end ofits g` 'nnjec :dito power line LI and it is connected,1 intermediate theends of its winding through' wiie 56',`contact R21), a wire 57, contactdLS1? and Wire 55 to power line L2. The other end of the winding ofmagnet R21 is conneied thleugh, a. Wire, Contact Rdl ai wire 5?;5 Wim?,iSledgwife 55 t0, Doveri linen.; O'Pmtionz,

If carriage 5v haswbeen movedto `the right', it wiulhav 'stoppedwnen @amsi depressedliniiit switch L'SZf' andthe" contacts ofthe switches will"be iril the positios'shown 46.

"To "cause `carriage""5"to` move farther utoward the right', limitswitches LSI Vand LS; 'are moved' toward the right by means of handl'eZuntil pointer123V' indicatesv upon' scialle` Eitlie' positionto"whichucarriager 5" i`s"to be moved," "Asl'soon as" button LSZCmovesfrom'v'hereath cani i?, switch LS? will .return to its nor alfposition whicll'wlll have nofflj 'attthi's til AS Witch LST "movestoward the, right," itsfuoutton fLS'lfI will be'-d'efprefssejdiby"canifi'an'd cause'fitvtc establish al circuit*LLReLa-Rzbeif LS'l'alSL-Li)V to effect 'operation of "relay "R2 toalpositionnin Whichcontacts R22t Aand uRZbfare open andcontacts'-R2`fand` R2l arey closed. Opening ,eliei R2? breaks theiruitihroeh ni iand' sivfitch 115|` returns ,to i't'sdnme :oefen S50-fa,itis; new tsrzteejjiti yond camp-r1 but Re negri-vigile ed' mit relay RIto open its contacts Ri, Rib andV Ric. Opening contact Ric preventsmagnet Rim from being reenergized when contact LSIb closes. Openingcontacts Rie and Rib has no effect as magnet CIm is energized by thecircuit through contact CIc and as magnet C2m is not energized at thistime.

As carriage 5 continues toward the right, it will iirst permit limitswitch LSI to return to its normal position and then it will depresslimit switch button LS2c to close contact LSZ and open contact LS2l. Thereturn of limit switch LSI to its normal position and the opening ofcontact LS2b have no effect at this time but closing contact LS2aestablishes a circuit (Li-R2@- 58-R2d-59-LS2B-55-L2) which causes relayR2 to close its contacts R2a and B2b and to open its contacts R2c andR2d.

Closing contacts R2a and R2b has no effect at this time. Opening contactR2d breaks the circuit through magnet R2m. Opening contact R2c breaksthe circuit through magnet Cim which permits the contacts Cia, Cib andCIc to open and contact Cid to close. Closing contact Cid has no effectat this time. Opening contact Cic prevents magnet Cim from beingenergized in response to relay Ri being closed. Opening contacts Cia andCib deenergizes solenoid Ci which permits spring i5 to return valveplunger 9 to its central position in which position it cuts off deliveryof liquid to cylinder I and blocks the end of channels iI and i2 toprevent further movement of piston 2 so that carriage 5 is stopped andpositively held in the posit-ion indicated upon scale 2li by pointer 23.

When carriage 5 stops, cam I'i will hold limit switch button LSZcdepressed and the other switches will be in their normal positions. Thatis the switch contacts will be in the positions indicated in Figs. 5 and6 so that, if handle 22 is again moved toward the right, the abovedescribed cycle of operations will be repeated.

To cause carriage 5 to move toward the left, limit switches LSI and LS2are moved toward the left by means of handle 22 until pointer 23indicates upon scale 2li the position to which carriage 5 is to bemoved. As soon as button LS2c moves from beneath cam I'i switch LS2 willreturn to its normal position which will have no effect at this time.After limit switches LSI and LS2 have been moved to the desiredposition, starting switch SS is closed which causes relay Ri to closeits contacts Ri, RIb and RIc as previously explained. Closing ContactRIb has no effect as contact R2c is open but closing contact RiCestablishes a circuit to hold relay Ri closed when switch SS is releasedas previously explained. Closing contact Ria establishes a circuit(LI-C2m-44-Cifl-45-R2aliii-Ria--li'i--Lm to energize magnet C2m whichcauses contactor C2 to open its contact C2d and to close its contactsCia, CIb and CIO. Opening contact C2d has no effect but closing contactC2c establishes a circuit (45 48 C2c 49 L2) around contact Ria to keepmagnet 02m energized when relay Ri opens. Closing contacts C2i and C2bestablishes a circuit (LI-35-C2L- 34-S2-36-C2b-3'i--LD to energizesolenoid S2 which will shift valve plunger 9 toward the left into theposition shown in Fig. 4. Then liquid will flow from pump 6 throughchannel 8, valve body I0 and channel i2 to the right end of cylinder Iand cause piston 2 to move carriage 5 toward the left.

As carriage 5 approaches the position indicated by a pointer 23, cam I1will rst depress limit switch LS2 the contact LSZb of which Will breakthe circuit through magnet Rim which will permit relay Ri to open itscontacts Ria, Ri1D and RIC. Opening contact RIc prevents magnet R-iInfrom being reenergized when contact LS2b opens. Opening contacts Ria andRib has no eifect as magnet C2m is kept energized by the circuit throughcontact C2c and as magnet Cim is not energized at this time.

As carriage 5 continues to move toward the left, it will rst permitlimit switch LSZ to return to its normal position and then it willdepress limit switch button LSIc to close contact LSIa and to opencontact LSI". The return of limit switch LS2 to its normal position andthe opening of contact LSIb has no effect at this time but closingcontact LSIa establishes a circuit (L I-R2m-5i-R2b-5'i-LS I a 5E- LD toenergize magnet R2m which will cause relay R2 to open its contacts R2aand R210 and to close its contacts R2c and R2d. Closing contacts R2c andR2d has no effect as contacts Rib, CIc and LS2au are open. Openingcontact B2b has no effect as relay R2 is kept operated by the residualmagnetism in the frame of its magnet R2m. Opening' contact R2n breaksthe circuit through magnet C2m which permits contactor C2 to close itscontact 02d and to open its contacts 02a, C2b and 02.

Opening contact C2c and closing contact C2d have no effect at this timebut opening contacts C2a and 02h deenergizes solenoid S2 which permitsspring iil to return valve plunger t to its neutral position and therebypositively stop carriage 5 in the position indicated upon scale 25 bypointer 23 as previously explained.

If limit switches LSI and LSZ are again moved toward the left, switchLSI Will return to its normal position as soon as its button LSIc passesfrom beneath cam ii and limit switch LS2 will be momentarily operated toclose its contact LSZ and open its contact LS2b as its button L2C passesbeneath cam I1. The return of limit switch LSI to its normal positionand the opening of contact LS2b will have no effect but closing contactLSE@ will establish the circuit through magnet R2m to cause relay R2 toreturn to its normal position as previously explained. As soon as buttonLS2c passes beyond cam ii, limit switch L52 will return to its normalposition which will have no effect. Then closing starting switch SS willinitiate a cycle of operations to cause carriage 5 to be moved towardthe left and stop in the position indicated by pointer 23 as previouslyexplained.

By so locating limit switches LSI and LS2 and so designing cam I1 thatthe contact a of one limit switch will be closed the instant after thecontact a of the other limit switch opens, carriage 25 may be moved toand positively stopped in a position within a few thousandths of an inchof the position indicated by pointer 23.

The control described herein may be modified in various ways and adaptedto various uses without departing from the scope of the invention whichis hereby claimed as follows:

` l. In a hydraulic transmission which includes a reciprocating motorfor moving a load in opposite directions selectively and a source ofmotive liquid connected to said motor to energize the same, thecombination of a piston valve connected between said motor and saidsource to control said motor, said valve being biased to a neutralposition in which it prevents flow of liquid to or from said motor andbeing movable T into ay rst or: a4 secondi operative position which, itdirects liquid. to" one or the other end' of said motor; a.; 'rst and asecond magnetic. device adapted' When energized selectively to moveseid. valve into; said rst' or said second' positions respectivel'm anelectric circuitfor' energizing devices selectively including a.starting switch, a controli element movable ina path parallef' to thepath of saidiloadand adapted. to be moved'in either of said directionsinto a selected position, means included'. in saidl circuit andresponsive to movement of said` control. element in the irstL or.' thesecond of saidl directions for causing the first or the second ofsai'd'devices to ce energize-:ii response to operation of said;starting'switch; and thereby. cause said' motor. to. move saidvload"inthe rsti or the secondof said'opposite' direc".- ti'ons. respectively,limit switch means movable' with said' control element' and adapted'when operated to effectdeenergization of Vthe' energized device, and acam movable. With saicl'loa'd" and' adaptedlinresponse t'o saidloadbeing movediinto'. a. posit'imV corresponding. toA said selectedposition to. operate sai'd. limit switchmeans and'ltiereby cause.saicl'energi'zed'device to ce deenergiZ-ed anzi permitsaidLvalv-etolreturnto its nenti-ai position andcause said'. motor to st'op saidload in said' corresponding, position.

21 Alcontrol accordihgtofcl'aim Lin which said control element. carries.at` a. point-remote from. saidloadan indicator for indicating theposition to which said Ioadlis to bemoved'.

3.. A controaccordint'o claim rin-Which said' electric circuitincludsarelayirselectin'g which of`saidtwo devieesshalbe energized' inresponse.- to. operation o' sail. starting. switch and'. switch meansmovable with. saidv element and operalle. by saidfcam ,to effect.operation.. of said". relay.

4.. ccntroll accordingtoclaiin 11 including a slidewhich ismovakilein.a.. patliparallel' to the.- pathof saidloadlanwliicli supportssaid'limitv switch. means. in the path. of said'. cam and an, elementarranged;at.a.distance from4 saidswitcli means; anchY connected` to.said?. slide. for. moving saidsvvitchmeanseinto. selcteclfnositions.

T. Ina. hydraulic. transmission whiclisinclds asource of. motiveliquiiiamotor. for moving a load! and twoconnections.. through one or theothenofwlicl liquidinay now. from saidsource to..said.motor.ancllcauseitto. move sairlload'inr oneor. the other,of'two.directions,the combination of! flow. controlf. means biasedf to, a neutral,`position .in which.. itl. prevents. flow'. of..` lic'iuidv to said'motor andmovab'l into. one orv theother of.'

two. operativepositionsein whichit. directsliquid'from saidfsourceto.saidmotor through onev or. the other.offsaidlconnections, aerstmagnetic.deviceadaptedwhen energzed'tomove Asaidflvv control means.. into, oneoperative. positionV Which it .directslquitofsaid 'motonthrough one. ofsaid connections.tocausesaidmotonto move said.V load in the.1rst.of..said rdirectionsrasecond magnetic Adevice.'adaptedwhenenergiz'edtemove. said..ow. controlimeans into. anotheroperativeposition in whichit :directs liq-uidlto saidlimotori through the other:of saidlconnectins to. cause said motor. to move.. said.. loadin .thesecond'lof said. directions, .a control .element .movablefin one. or.theother ofesaiddii'ections .-tok aselected '.pos-Y l or the secoue'Yof seid directions for causing"` the:

' rst or the second of sedoevices' to beener-giid ergi'zed device and e:dem movoisievvitiijsoid" lodf' and adapted inresponsejtosaid lofa'd'beiiigniovd to' a position corresponding'to saidseleoted position.Y to'operaie said' liiiiit. s vviteli esfani thereby c'ause` saii device" tobei dei'gik'el afi permit said' flovsrc'on'trolA means" t`o return` t'oits neutral' position' and c'euse sani motor* to stop said load insaidcorrespordirfg'posit'ol 6; AV contro1aoeording-to eiii in wnclsidcontrol" ele'rnen't cerries at'. apoint remote from' said .loadenind'ic'atr for" indicating. the. positionto`which saidlondiisrtobemoved- '7i A control' for ai tra'sissiiiaccordlg t' claim; 6 in whichsa'id motor corn-prises a piston'- sne e. cviinderend-saidow controlineens coiiprisesN a' valve which' wlenin. itsneutrel positioni'rlziiocksb'otli ends ofsaidcylinders 9i A" eontrolaccorih'gtoelirn5l`vvhich'saii electric circuitirlclde's 'arelay for 'selecting :whichof said. tWo devices shall be` energized iii' response to" operation: ofsoi-cr starting. switen and" s'v'vitbn move-bie' Wfitii` said"elementand operableA b'y said cani" to effectL o'ert/ionof said'relay".`

1ct control'accordingto" omni finoieiige; snee which' is: movablev in.eapath parallel to' the path offsa'idJ load and which' supports saidlimit' swtch nii-fansin' the p'atli'l of said= c`a'ii1`,'. an'da'nrelementerrang-eerente disteneelfoi seid switch means iandc'onnecte'df.to said: slide for? nio-ving? ssidswiteh means 'into seiet'ed positions.

11i A contrer ecco-renne' to demi" 10l iieiig. a ststionery'soele; anotepointermovable wtiil soier eiemen'c remedie-ating;uponisaieseeie the"pesmemrxtowhiohsedazione"isrto' Uemovedl RANSOM References Gtd.; the".Tie' Ofi this3 patet UNITED" ESTATS"l Greet-Briten Fb: 2'2194c

